Difference Between Transmission Fluid And Brake Fluid

Last Updated on January 24, 2023 by Leepu Da Maxim

Transmission fluid is used to lubricate the gears and components of a vehicle’s transmission while brake fluid is used to transfer force from the brake pedal to the brake pads to slow or stop a vehicle.

Key Takeaways

• Both transmission fluid and brake fluid have specific properties so you can’t interchange them
• Transmission fluid is made from a combination of base oils and additives
• Brake fluid is made from a combination of glycol and silicone-based compounds
• Transmission fluid requires regular changes compared to brake fluid to maintain proper lubrication and cooling of the transmission

Main Differences Of Brake Fluid And Transmission Fluid

Features	Transmission Fluid	Brake Fluid
Operating area	Transmission fluid is incorporated into the vehicle’s manual or automatic transmission	Brake fluid is incorporated in the brake system that operates from the brake pedal to all four wheels
Main function	It is responsible for lowering the temperature and providing lubrication to the transmission	It is responsible for transmitting power and pressure from the brake pedal to all four wheels
Lubrication capacity	It has a high lubrication capacity	It has an intermediate lubrication capacity and other qualities
Fluid types	There are at least 6 types of transmission fluids	There are generally 4 types of brake fluids
Routine maintenance	A hobbyist can incorporate transmission fluid into his vehicle	It is necessary to have a professional fit the brake fluid to a vehicle

What Are The Differences Between Brake Fluid And Transmission Fluid?

As with any vehicle, a car needs several fluids to function. All these fluids are really necessary to have a vehicle in good condition. In this sense, both brake fluid and transmission fluid are necessary. Each of these fluids has a certain life span, so they must be replaced from time to time.

Also, these two fluids are usually checked and replaced regularly along with routine maintenance. However, brake fluid is not the same as transmission fluid. Each of these fluids is in different locations and has different functions.

Transmission Fluid

Of course, transmission fluid is incorporated into any type of vehicle. In this sense, it is necessary to use transmission fluid so that the car can function properly. Whether it is manual transmissions or automatic transmissions, it is necessary to incorporate transmission fluid. 

In both cases, this type of fluid allows flexible operation without any friction. In turn, transmission fluid can also be very useful for transmitting power more easily while also acting as a coolant. Especially these features are incorporated for automatic transmissions. So, the main features and functions of transmission fluid are:

1. The fluid allows for protection and cleans each of the metal surfaces involved and decreases wears.

2. The transmission fluid allows us to care for and maintain the transmission seals in good condition.

3. Temperatures can be reduced during operation and cooling functions are optimized with the transmission fluid.

4. The temperature range is optimized while increasing the rotational speed in the transmission.

In this regard, different types of transmission fluids can be adapted to different types of vehicles. Of course, knowing each of these types of transmission fluid allows you to incorporate the right choice for each vehicle.

All of these transmission fluids do not work in manual transmissions and automatic transmissions. In turn, not only can high temperatures be reduced, but the transmission cannot count on long service life.

1. Mercon – Dexron: In particular, this is the transmission fluid used for automatic transmissions these days. In this case, the various moving parts are protected from excessive friction and high temperatures.

2. HFM Fluids: In this case, it is a type of transmission fluid very similar to the previous one. However, they are highly friction-modified fluids to offer a much more efficient functionality in the face of the friction problem.

3. Synthetic Fluids: About the first option, this type of transmission fluid is usually much more expensive. However, the protection against shear, oxidation, and friction is of higher quality. Additionally, sudden temperature changes will not be a problem with this transmission fluid.

4. Type F: Those vehicles that are 1970’s models require this automatic transmission fluid. The difference with the previous transmission fluids is that this option does not contain friction modifiers.

5. Hypoid Gear Oil: In this case, it is a fluid that is usually incorporated into some vehicles with manual transmissions. This option allows it to cope with extreme temperatures and withstand high pressures.

6. Engine Oil: Engine oil is one of the most common fluids and is used to lubricate the various moving parts of the engine. The properties and composition of motor oil are very similar to those of gear oil.

Brake Fluid

Brake fluid is used to optimize and ensure the correct functioning of the vehicle’s brakes. In this case, it is necessary to transmit a certain pressure starting at the brake pedal. So, this fluid transfers the power from the master cylinder to the wheel cylinders. 

This is why it is very necessary to apply the correct maintenance to the brake fluid. Both humidity and contamination of different components can be a problem. In this sense, excessive humidity can damage the correct functionality of the brake fluid, and therefore of the brakes themselves.

Thus, both brake fluid and transmission fluid have different compositions and different functionalities. The only similarity between these two fluids is that they are required in a vehicle for proper overall operation. The main characteristics and functions are:

1. Transfers movement and pressure from the brake pedals to all four wheels.

2. It prevents high temperatures from being a problem for the vehicle components.

3. Brake fluid is responsible for absorbing moisture and preventing it from boiling over.

4. Brake fluid also prevents corrosion and provides a certain amount of lubrication to the moving parts of the brake system.

5. This is why brake fluid must remain fully fluid and not solidify regardless of the temperature.

6. Brake fluid is an essential part of routine vehicle maintenance.

It is a very dangerous fluid, so it is necessary to be very careful when using brake fluid. Here are some additional tips.

1. A car that uses DOT 3 or DOT 4 should not use DOT 5.

2. A car that uses DOT 3 can use DOT 4 but not the other way around.

3. Do not replace brake fluid with another fluid.

4. Brake fluid can cause severe damage to painted surfaces.

5. It is necessary to clean the skin efficiently after contact with the brake fluid.

6. In vehicles with ABS brakes, it is not possible to mix DOT 5 with glycol fluids.

References:

https://itstillruns.com/difference-brake-fluid-transmission-fluid-6787331.html

https://www.motor.com/magazine-summary/mastering-basics-fluid-selection-november-2003/